1990 Volume 8 Issue 2 Pages 261-267
A series of studies has been performed with an objective of applying "Photo-acoustic spectroscopy (PAS)" as NDT to thermal sprayed specimens. In this report, the authors have developed a prototype instrument of PAS in order to apply to solid specimens with and without thermal spraying coatings, and basically studied PA characteristics of mild steel and copper spray deposited specimens.
The main result obtained are as follows; The prototype instrument was able to apply to solid specimen with and without thermal spraying coating by using double beam method. As for PA characteristics of mild steel, it increased with decreasing of light wavelength and increasing of specimen volume, and was almost constant for specimens of which thickness was over than 2 mm. As for PA signal intensity of mild steel with copper spray coating, it decreased with increasing of light wavelength.